Astm d 2358 16

Designation D2358 − 16 Standard Test Method for Separation of Active Ingredient from Surfactant and Syndet Compositions1 This standard is issued under the fixed designation D2358; the number immediate[.]

Designation: D2358−16

Standard Test Method for

Separation of Active Ingredient from Surfactant and Syndet

This standard is issued under the fixed designation D2358; the number immediately following the designation indicates the year of

original adoption or, in the case of revision, the year of last revision A number in parentheses indicates the year of last reapproval A

superscript epsilon (´) indicates an editorial change since the last revision or reapproval.

1 Scope

1.1 This test method covers the procedure for the separation

and purification of active ingredient from surfactants and

syndet compositions The separated active ingredient may be

used for qualitative examinations This test method also

permits the estimation of total active ingredient level present in

the sample under test

1.2 This test method yields the active ingredient together

with other alcohol-soluble materials and therefore is useful

only in estimating the actual active ingredient level Correction

for the amount of the most common contaminant, sodium

chloride, is shown by a separate determination

1.3 The values stated in SI units are to be regarded as

standard No other units of measurement are included in this

standard

1.4 This standard does not purport to address all of the

safety concerns, if any, associated with its use It is the

responsibility of the user of this standard to establish

appro-priate safety and health practices and determine the

applica-bility of regulatory limitations prior to use Material Safety

Data Sheets are available for reagents and materials Review

them for hazards prior to usage

2 Referenced Documents

2.1 ASTM Standards:2

D1681Test Method for Synthetic Anionic Active Ingredient

in Detergents by Cationic Titration Procedure

3 Summary of Test Method

3.1 The test method involves the extraction of the active

ingredient with alcohol Reprecipitation of the insolubles is

specified to remove the last traces of active ingredient Dilution

of the alcoholic extract to a known volume and the evaporation

of a suitable aliquot permits measurement of total alcohol-soluble matter An estimation of sodium chloride content is made so that a corrected total active ingredient level may be obtained Provision is made for purification of the active ingredients in Section13

3.2 Purity of Reagents:

3.2.1 Reagent grade chemicals shall be used in all tests Unless otherwise indicated, it is intended that all reagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society, where such specifications are available.3Other grades may be used, pro-vided it is first ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accuracy of the determination

3.3 Unless otherwise indicated, references to water shall be understood to mean distilled water or water of equal purity

SEPARATION OF TOTAL ALCOHOL-SOLUBLE

MATTER

4 Reagents

4.1 Ethyl Alcohol (95 percent)—Freshly boiled ethyl alcohol

conforming to Formula No 3A or No 30 of the U S Bureau

of Internal Revenue The alcohol should not be neutralized Redistilled alcohol shall be used if alkali absorption is more

than 0.2 mL of 0.1 N NaOH solution/100 mL of alcohol 4.2 Ethyl Alcohol (Absolute)—Freshly boiled 200-proof

ethyl alcohol conforming to either Formulas No 3A or No 30

of the U S Bureau of Internal Revenue

4.3 Phenolphthalein Indicator Solution (10 g/L)—Dissolve

1 g of phenolphthalein in 50 mL of ethyl alcohol (95 %) and then mix with 50 mL of water

4.4 Sulfuric Acid (1 + 100)—Add 1 mL of concentrated

sulfuric acid (H2SO4, sp gr 1.84) to 100 mL of water

1 This test method is under the jurisdiction of ASTM Committee D12 on Soaps

and Other Detergents and is the direct responsibility of Subcommittee D12.12 on

Analysis and Specifications of Soaps, Synthetics, Detergents and their Components.

Current edition approved July 1, 2016 Published August 2016 Originally

approved in 1965 as D2358 – 65 T Last previous edition approved in 2009 as

D2358 – 89 (2009) DOI: 10.1520/D2358-16.

2 For referenced ASTM standards, visit the ASTM website, www.astm.org, or

contact ASTM Customer Service at service@astm.org For Annual Book of ASTM

Standards volume information, refer to the standard’s Document Summary page on

the ASTM website.

3Reagent Chemicals, American Chemical Society Specifications, American

Chemical Society, Washington, DC For suggestions on the testing of reagents not

listed by the American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and National Formulary, U.S Pharmacopeial Convention, Inc (USPC), Rockville,

MD.

5 Safety Precautions

5.1 Formulas No 3A and No 30 ethyl alcohols are

dena-tured alcohols They are health hazards and flammable liquids

See manufacturer’s label warning as to use, safe handling, and

disposal

5.2 Sulfuric acid is corrosive Use proper protective

equip-ment including adequate eye protection If acid contacts the

body or is splashed in the eyes, flush the affected parts with

water for at least 15 min Obtain medical attention

6 Procedure

6.1 Weigh out a sample, to the nearest 0.01 g, to correspond

with the levels of active ingredient prescribed in Table 1and

transfer to a 600-mL beaker Liquid samples containing high

levels of water should be evaporated to a pasty consistency

after weighing Samples containing high levels of hydrated

alkaline salts should be dried in an oven at 105°C for 1 h after

weighing

6.2 Add 300 to 350 mL of hot 95 % alcohol Cover with a

watch glass and heat on a steam bath for approximately 11⁄2to

2 h, stirring frequently to disperse the solids and break up any

lumps

6.3 Remove the beaker from the steam bath and permit the

insolubles to settle for a few minutes Add 2 drops of

phenolphthalein indicator solution If the solution is pink,

neutralize with 1 N H2SO4using no more than 1 mL Samples

containing high levels of free alkali, requiring more than 1 mL

of 1 N H2SO4, should be neutralized with H2SO4 of higher

concentration to limit the amount added to less than 1 mL

Before proceeding, make the solution just alkaline with 0.1 N

NaOH solution If the solution is acid originally, neutralize the

free acid with alcoholic NaOH solution to the phenolphthalein

end point Decant the alcoholic solution through a suitable

filter, retaining as much as possible of the insoluble matter in

the beaker Collect the clear filtrate in a suitable filter flask or

beaker

6.4 Add 50 mL of hot 95 % alcohol to the residue in the

beaker and bring to boiling on a safety hot plate Let the

insolubles settle and decant the alcoholic solution through the

filter as before Repeat the extraction of the insolubles with an

additional 50 mL of 95 % alcohol, retaining the bulk of the

insolubles in the beaker

6.5 Evaporate the residual alcohol from the residue in the

beaker on a steam bath, stirring at intervals to permit complete

evaporation of the solvent Dissolve the residue in the beaker in

a minimum volume of hot water, not to exceed 10 mL, heating

on a steam bath to effect solution

6.6 Dilute the water solution with 200 mL of hot absolute alcohol Bring to a boil on a steam bath and filter through the previously used filter, combining the filtrate with the initial alcoholic filtrate Wash the beaker and residue several times with hot 95 % alcohol, transferring the insolubles to the filter with several small portions of hot 95 % alcohol

6.7 Evaporate the combined alcoholic filtrate and washings

to approximately 450 mL and transfer to a 500-mL volumetric flask Cool to room temperature and dilute to volume with

95 % alcohol Mix well

6.8 Pipet a 100-mL aliquot into a tared flask and evaporate

to dryness on a steam bath Place in an oven maintained at 105

6 2°C and dry for half-hour periods to constant weight

7 Calculation

7.1 Calculate the percentage of total alcohol-soluble matter

as follows:

Total alcohol 2 soluble matter, % 5@~W 2 T!/S#3 100 (1) where:

W = weight of dish plus alcohol-soluble matter, g,

T = weight of dish, g, and

S = grams of sample in aliquot taken

CORRECTION FOR SODIUM CHLORIDE

CONTENT

8 Procedure

8.1 Pipet a suitable aliquot from the solution as prepared in

6.7into a 400-mL beaker Evaporate to a volume of about 30

mL and dilute to 100 mL with water Add 2 drops of methyl orange indicator solution and acidify to the acid color by using HNO3(1+4) Warm slightly, stir, and add 50 mL of acetone Follow the procedure for quantitative determination, starting with 13.2 of MethodD1681

9 Calculation

9.1 Calculate the percentage of sodium chloride (NaCl) as follows:

NaCl, % 5@~B 3 N 3 0.05845!/S#3 100 (2) where:

B = millilitres of AgNO3solution used,

N = normality of the AgNO3solution, and

S = grams of sample in aliquot taken

TOTAL ACTIVE INGREDIENT

10 Calculation

10.1 Calculate the corrected alcohol-soluble matter, which

is a measure of the total active ingredient, as follows:

Alcohol 2 soluble matter, corrected, % 5 A 2 C (3) where:

A = percentage of total alcohol-soluble matter (Section 7), and

C = percentage of NaCl (Section 9.)

TABLE 1 Active Ingredient Level Expected

Active Ingredient Level Expected, % Weight of Sample, g

PURIFICATION OF TOTAL ALCOHOL-SOLUBLE

MATTER

11 Reagent

11.1 Acetone-Ether Mixture (1+1)—Mix 1 part of acetone

with 1 part of ether

12 Safety Precautions

12.1 Acetone is a flammable solvent and a health hazard

This test should be performed in a well-ventilated

explosion-proof area and protective gloves and garments should be used

12.2 Ether is a skin, brain, and kidney irritant and an

extreme fire and explosion hazard All precautions should be

taken to proceed with this test only in a special explosion-proof

area and under a special explosion-proof hood Protective

gloves and garments should be used

N OTE 1—See special instructions on manufacturer’s label for acetone

and ether warning and disposal.

13 Procedure

13.1 To the dried residue from 6.8 add 50 mL of ac-etoneether mixture and warm on a steam bath

13.2 Agitate with a glass stirring rod and filter while warm through a general-purpose acid-washed filter paper Collect the filtrate in a small beaker Wash the paper with a few small volumes of acetone-ether mixture

13.3 Evaporate the combined filtrate and washings on a steam bath Dry the residue in an oven at 105 6 2°C

N OTE 2—The evaporated fraction may be used for infrared spectropho-tometric or qualitative examination If the sample size is insufficientfor these purposes, a larger aliquot may be taken for evaporation.

14 Keywords

14.1 active ingredient; alcohol extraction; surfactant com-positions; syndet compositions

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